Monkeys learn to play ‘chicken’ in a virtual driving game

Monkeys have something in common with daredevil teenagers: an aptitude for the potentially deadly car driving contest, “chicken”.

In the human version of the game, two people drive their cars towards each other down a long, straight road. Whoever turns aside first is the chicken; if neither does, there’s a head-on crash.

Four macaques were trained to play a version of this nerve-testing game on a computer, getting rewards of fruit juice if they avoid a crash. They were given the most juice if they were the one who didn’t give up and swerve.

Advertisement

In parallels with human social mores, more submissive monkeys were more likely to swerve. “Hierarchy really matters,” says Wei Song Ong, of the University of Pennsylvania. “It’s a bit like James Dean.”

Pairs of macaques played the game while sitting across from each other at a table-top computer screen, using joysticks to control their cars. As well as watching the progress of their cars on the screen below, Ong’s team found that the monkeys often looked at each other’s eyes.

Don’t flinch

Monkeys that were about to yield tended to look to the side of the screen, where their car was about to veer off – information that could be exploited by their partner to avoid yielding if the other is about to. “If one monkey sees the other is looking at the swerve target, we think they are attributing intention to that,” says Ong.

When monkeys played against a computer, rather than each other, more crashes occurred, suggesting that the monkeys do get useful information from the direction of their partner’s gaze.

Ong says the findings shed more light on macaques’ abilities to make deductions about other individuals’ mental states – known as “theory of mind” – a capacity that is most developed in humans. “For theory of mind, it helps to be able to follow the gaze,” says Ong. The team’s findings were presented at the Society for Neuroscience meeting in Washington, DC, this week.